Subcellular distribution of Ag, Cd, Co, Cu, Fe, Mn, Pb and Zn in the digestive gland of the common cuttlefish Sepia officinalis

International audienceThe subcellular fractionation of the digestive gland cells of the common cuttlefish Sepia officinalis was performed in order to investigate the distribution of metals 1) between organelles and cytosol and 2) in the different cytosolic fractions separated by gel-filtration chromatography. Total metal concentrations vary over 3 orders of magnitudes, ranging from 2.2 µg.g-1 dwt for Pb to 612 µg.g-1 dwt for Zn. With the exception of Cd, Co and Cu, metals were mostly bound to the organelles. Whereas no specific organelle compartment was found for Mn, Pb and Zn, Fe was mainly associated to nucleus, brown body, and “boule” fraction (i.e. 52%) and 44% of the total Ag was contained in the lysosomal and mitochondria enriched fraction. The link of metals with hydrosoluble proteins in the cytosolic fraction was investigated at 254 and 280 nm. Direct relationship between cytosolic metal and metallothioneins could only be established for Ag and Cu whereas Cd and Zn seems to mainly bind high (>70kDa) and low (< 4kDa) molecular weight protein